Cyclonic separator



Filed March 25, 1964 F m m WW V N M 6 m M m 35 w W 3r r United States Patent Filed Mar. 23, 1964, Ser. No. 353,823 4 Claims. (Cl. 55-191 This invention relates to the deaerating of fluent liquid slurries and the like, and particularly to slurries containing pulp stock being conditioned for paper making.

The object of the invention is to simplify the construction as well as the means and mode of operation of separators, whereby such separators may not only be economically manufactured, but will be more eflicient and satisfactory in use, adaptable to a wide variety of application, .and be unlikely to get out of order.

An object of the invention is to reduce the amount of air carried to the pressure screens and the pressure headbox of a paper machine with a supplied pulp slurry, the operation of these devices being materially affected by the presence of excessive air in the slurry.

Another object of the invention is to minimize bubbling and frothing on the Fourdrinier wire section, due to released air, while enabling the pulp fibers to arrange themselves in a more uniform layer thereon, giving a better paper formation.

A further object of the invention is to achieve pulp deaeration as described according to an apparatus combining the deaerating function with a pulp cleaning function, especially one utilizing the elutriation principle of adding supplemental liquid to a dirt-rich fraction of the slurry.

Still another object of the invention is to utilize the central liquid-free core of a hydro-cyclone as the flow path for withdrawn air, a feature of the invention residing in the use of an elutriation device at the rejects end of the hydrocyclone presenting a discharge orifice on the same axis as the liquid-free core whereby such core may extend through the elutriation device and be connected beyond such device to a source of vacuum. A further object of the invention is to provide separators possessing the advantageous structural features, the inherent meritorious characteristics and the mode of operation herein mentioned.

With the above and other incidental objects in view as will more fully appear in the specification, the invention intended to be protected by Letters Patent consists of the features of construction, the parts and combinations thereof, and the mode of operation as hereinafter described or illustrated in the accompanying drawings, or their equivalents.

Referring to the accompanying drawing wherein is shown one but obviously not necessarily the only form of embodiment of the invention,

FIG. 1 is a view in side elevation, partly diagrammatic, of apparatus accomplishing deaerating and dedirting functions in accordance with instant inventive concepts; and

FIG. 2 is a view of the apparatus of FIG. tudinal section, some parts being omitted.

Like parts are indicated by similar characters of reference throughout the several views.

Referring to the drawings, the combined hydrocyclonic cleaner and deaerator selected as the illustrated embodiment of the invention comprises a main section 10 essentially conical in form and for convenience of manufacture and parts replacement made up of three relatively detachable portions 11, 12 and 13. To the apex end of section 10 is fitted an elutriation device 14. The base end of section 10 projects in cylindrical form to define an ex.

1 in longitended portion 15 integral with portion 11. While operationally independent of attitude, the apparatus will for convenience of description be referred to as occupying the upright vertical position illustrated. In this sense the device 14 may be considered attached to the lower end of section 10 and cylindrical portion 15 considered to represent an upper reach or upper end of such section.

The conical section 10 is open in its interior to define a separating chamber 16. Portion 13 at the apex end is truncated at its tip and defines an opening 17 in the longitudinal axis of section 10. The opposite end of the cone section, as defined by the upper end of cylindrical portion 15, is closed by an insert 13 overlaid by a flange 19. Installed in closure 18 and flange 19, in a manner to project within and without chamber 16, is an open ended tube 21, the tube being centrally disposed in the longitudinal axis of section 10 in alignment with opening 17. Beneath closure 18, cylindrical portion 15 is formed with a lateral opening 22 through which a fluent liquid slurry is received into chamber 16, the arrangement and location of opening 22 being such as to achieve a tangentially directed flow of the incoming slurry relative to the Wall of chamber 16. Means including a fitting 23 conducts the slurry to inlet opening 22. The apparatus of the inventive embodiment is incorporated into a system circulating the slurry under pump pressure, which system may include treatment stations additional to the deaerating cleaner here illustrated at locations either upstream or downstream thereof relative to the slurry flow.

The slurry is in the instance of the illustrated form of the invention an aqueous cellulosic pulp suspension. It contains, however, in addition to liquid and usable pulp fibers, an amount of air which would be considered excessive if allowed to reach the paper making machine, as well as dirt, which term is used generally to define unwanted and unusable materials such as bark specks, shives, sand, grit and the like.

Within chamber 16 the introduced slurry develops a rotating motion, and, in response to continuing slurry introduction, moves progressively from the base end of cone section 10 toward the apex end thereof. Flow velocity increases as the cross-sectional area of chamber 16 decreases and a somewhat complex pattern of forces results producing an outer descending vortex 24 and an inner ascending vortex 25. In general, liquid and relatively light usable fibers transfer from the outer vortex to the inner vortex and rise as an acceptable slurry fraction to and through the tube 21 set in the base end of the unit. The remaining slurry fraction, rich in relatively heavier dirt particles, remains in the outer vortex and proceeds to opening 17 at the apex end of the unit whence it discharges as the rejected fraction. Some of the developed forces in the unit are (a) a pressure differential from the periphery of section 10 toward the center thereof and toward the truncated end of the cone, (b) a centrifugal force generated by the rotating slurry, and (c) an increase in tangential velocity from the periphery to the central region. The pressure differential induces motion toward the center of the unit and toward the apex of the cone. Fiber and dirt in passing through the fields of successively increasing centrifugal force tend to ances the radial flow will be carried down in this field by the downward component of liquid flow until it reaches the apex. The fibers have a high length to diameter ratio and present substantial surface to the radially moving liquid and are carried toward the center of the unit and finally upward in vortex 25 because of the increasing tangential velocity without serious entrainment of dirt. The dirt, together with some fiber, carries down toward the apex of the cone where it is continuously discharged through opening 17.

The centrifugal force developed in cone section results in formation of a liquid-free core 26 in the axis thereof. The core 26 is continuous throughout section 19, extending to and through apex end opening 17 and to and through the accepts discharge tube 21. Opening 17 is sized with regard to the diameter of the formed core 26 so that an annular space surrounding such core is provided adequate to the discharge of the rejected dirtrich fraction. Air carried with the moving slurry tends to move from the slurry into the core 26 of relatively reduced pressure.

In the interests of continuing the separation process beyond discharge opening 17, and under conditions conducive to good separation, there is fitted to the apex end of the cone section 10 the elutriation device 14 as before mentioned. This device comprises a cylindrical portion 27 receiving the apex end of cone section 10 and a frustoconical portion 28 forming a coaxial continuation of cylindrical portion 27 and connected thereto by sloping surface 29. Clamping means 31 attaches the fitting 14 to the section 10 in a substantially air tight manner. The truncated tip of frusto-conical portion 28 defines an opening in the form of discharge orifice 32. Intermediate its ends, in cylindrical portion 27, the device 14 is formed with a tangentially disposed downwardly inclined opening 33 receiving supplemental liquid through means including a fitting 34. The incoming supplemental liquid joins the swirling slurry discharging through opening 17. It imparts renewed energy of motion thereto and dilutes the slurry. As a result fibers trapped in the concentrated rejected fraction issuing from opening 17 are enabled more readily to move inward and to join or be drawn into the upwardly moving inner vortex 25 for removal through tube 21. Usable fibers, which would otherwise be lost, are thereby recovered from the rejected fraction while permitting the dirt to continue its downward path of travel.

The structure of device 14, as well as its manner of mounting to the cone section 10, is such as to make it in effect a coaxial extension of the section 10. The center line of the device, passing through cylindrical portion 27 and cone portion 28, is on the same axis as is cone section 10. Discharge orifice 32 is thus on the same said axis. As a result the conditions prevailing in the main separator portion of the unit continue throughout the device 14, the outer and inner vortices 24 and 25 continuing in uninterrupted manner to and through the device 14 and the liquid free core 26 extending in similar uninterrupted manner in the axis of the unit to and through discharge orifice 32. In the latter connection, the conditions developed within chamber 16, and continuing throughout device 14, tend to be projected through and beyond discharge orifice 32. The exiting slurry discharges as a spray with forceful components of radial outward motion, leaving a center area of low pressure into which the liquid free core 26 may extend.

Deaeration of the pulp slurry is accomplished by reducing the pressure in core 26 to a value less than that which is generated by the rotary motion of the slurry. According to a feature of the invention this reduction in pressure is brought about by applying vacuum to the core 26 through the elutriation device 14, such core being accessible through the discharge orifice 32 as above noted. In carrying out this concept there is provided in accordance with the illustrative inventive embodiment, a closed chamber 35 having an upwardly rising duct 36 receiving the conical portion 28 of device 14. A wear resistant liner 37 may be installed in duct 36. At its upper end the duct 36 is fitted to or connected to conical portion 28 in the region of sloping surface 29 by means of a coupling 38 establishing a substantially air tight connection between fitting 14 and duct 36. The latter is in turn connected in a substantially air tight manner to chamber 35. As a result the air pressure established in chamber 35 is communicated through duct 36 to discharge orifice 32 and to the liquid-free core 26 disposed centrally thereof.

In the operation of the unit discharged slurry collects in the bottom part of chamber 35 and is continuously or selectively drawn off through an outlet opening 39 in the bottom wall of the chamber. The upper part of the chamber 35 represents an air space and is connected through an upper outlet 41 to a source of vacuum which may be a vacuum pump or like device. By this means the pressure in chamber 35 may be reduced below that tending to be established in the core 26 by the centrifugal action in the separator. As a result air drawn into the core 26 is directed along the core toward and through the elutriation device 14 and into chamber 35 where it is evacuated through outlet opening 41. There is in the operation of the unit, therefore, a continual deaerating of the slurry so that neither the acceptable fraction which issues from tube 21 and is conducted to the paper machine nor the rejected fraction which falls to the bottom of chamber 35 and is carried off to subsequent treatment or to waste contain excess air.

The discharge orifice 32 is sized, like the discharge opening 17, to accommodate the core 26 while retaining an annular space thereabout for discharge of the rejected fraction. Thus the core is enabled to retain its identity as a fiow path for released air to and through the orifice 32 without impairment of the slurry discharge process.

From the above description it will be apparent that there is thus provided a device of the character described possessing the particular features of advantage before enumerated as desirable, but which obviously is susceptible of modification in its form, proportions, detail construction and arrangement of parts without departing from the principle involved or sacrificing any of its advantages.

While in order to comply with the statute the invention has been described in language more or less specific as to structural features, it is to be understood that the invention is not limited to the specific features shown, but that the means and construction herein disclosed comprise but one of several modes of putting the invention into effect, and the invention is therefore claimed in any of its forms or modifications within the legitimate and valid scope of the appended claims.

Having thus described my invention, I claim:

1. A deaerating separator comprising a conical wall section forming a chamber having base and apex ends and an inlet in its base end for tangential inflow of an air entraining liquid slurry, said chamber so formed being operative to produce therein a separation of said slurry into accepted and rejected fractions which counterfiow in concentric columns and produce a central coextensive liquid-free core, means defining an elutriation chamber having one end connected to the apex end of said conical section, said means defining said elutriation chamber having a cylindrical form to the end thereof connected to said conical section while its remote end has a conical form the tip of which provides an opening from said elutriation chamber having a diameter exceeding that of said core, said elutriation chamber forming a direct extension of said separating chamber and having an inlet for tangential inflow of a supplemental liquid at a location adjacent said apex end of said conical section to produce thereby a continuation of the counterfiowing columns which defines an extension of the liquid-free core, said elutriation chamber being so formed that the rejected fraction issues therefrom in a pattern which defines an extension of said liquid-free core and means defining a further chamber in direct communication with said elutriation chamber, said further chamber having means in connection therewith for applying a vacuum to the end of said liquid-free core accessible in said chamber to thereby draw from said core the air entrained in the separated slurry and deliver it from said chamber and means providing for the separate withdrawal of said separated slurry to thereby inhibit the inclusion of excess air in either the accepted or rejected fractions which discharge from said separator.

2. A deaerating separator comprising a conical wall section forming a chamber having base and apex ends in cluding an inlet at its base end for a tangential inflow of an air entraining liquid slurry, said chamber being so formed to produce'therein a separation of said slurry into accepted and rejected fractions which counterflow in concentric columns and produce a central coextensive liquidfree core, air in the slurry being drawn into said core by generated centrifugal forces, means defining an elutriation chamber having one end connected to the apex end of said conical section, said means defining said elutriation chamber having a cylindrical form to the end thereof connected to said conical section while its remote end has a conical form, said elutriation chamber forming a direct extension of said separating chamber and having a discharge orifice generally coaxial with the apex end of said conical section, said elutriation chamber having an inlet for a tangential inflow of a supplemental liquid at a location adjacent said apex end of said conical section and being formed to produce thereby a continuation of the counterfiowing columns to define thereby an extension of the said liquid-free core, said discharge orifice being of a size to allow said core to extend to and through said orifice in a manner to provide a surrounding area for discharge of the rejected slurry fraction through said orifice, means defining a vacuum chamber having an inlet thereto and an outlet therefrom, an open ended duct connected at one end to form an extension of said elutriation chamber and have its projected extremity in connection with the means defining said vacuum chamber about the inlet thereto, said duct providing a channelling device for the rejected fraction and the extended core and said vacuum chamber having a discharge passage independent of its outlet for evacuation therethrough of air which reaches said core in the process of the slurry separation.

3. A deaerating separator comprising a wall section forming a chamber circular in cross-section and open to either end, said chamber having an inlet to one end for tangential inflow of an air entraining liquid slurry, said chamber being so formed to produce therein a separation of said slurry into accepted and rejected fractions which counterflow' in generally concentric columns and produce a central coextensive liquid-free core, centrifugal forces generated in said chamber inducing the movement of entrained air to said core, a fitting forming an extension of the other end of said separator section having first a cylindrical interior and a frusto-conical projected extremity spaced longitudinally from said separator section, said conical extremity terminating in a discharge orifice on the central axis of said separator section, means for introducing supplemental liquid to said fitting in a manner to entrain the rejected fraction issuing from said separator section and form an extension of said core to and through said orifice and means defining a chamber in connection with said fitting to receive the discharge therefrom and in part encompass the extension of said core, said chamher having an opening, the latter of which has a vacuum inducing means in connection therewith which directly communicates with and draws the air from said core to thereby inhibit the inclusion of excess air in either the accepted or rejected slurry fractions which discharge from said separator, and means for separately discharging the separated slurry.

4. A deaerating separator as in claim 3 characterized in that the projected extremity of said fitting is formed as a discharge nozzle the opening from which has a crosssectional area exceeding the cross-section of said core to provide thereby that the rejected fraction issue from said fitting about and in defining relation to an extension of said core.

References Cited UNITED STATES PATENTS 2,709,397 5/1955 Banning 210-512 X 2,809,567 10/1957 Woodrufi -459 X 2,816,490 12/ 1957 Boadway et a1 55-191 X 2,816,658 12/1957 Br-aun et al 210512 2,878,934 3/1959 Tomlinson 2l0512 X 3,163,508 12/ 1964 Tuck et a1. 55-46 REUBEN FRIEDMAN, Primary Examiner. SAMIH N. ZAHARNA, Examiner.

C. N. HART, Assistant Examiner. 

1. A DEAERATING SEPARATOR COMPRISING A CONICAL WALL SECTION FORMING A CHAMBER HAVING BASE AND APEX ENDS AND AN INLET IN ITS BASE END FOR TANGENTIAL INFLOW OF AN AIR ENTRAINING LIQUID SLURRY, SAID CHAMBER SO FORMED BEING OPERATIVE TO PRODUCE THEREIN A SEPARATION OF SAID SLURRY INTO ACCEPTED AND REJECTED FRACTIONS WHICH COUNTERFLOW IN CONCENTRIC COLUMNS AND PRODUCE A CENTRAL COEXTENSIVE LIQUID-FREE CORE, MEANS DEFINING AN ELUTRIATION CHAMBER HAVING ONE END CONNECTED TO THE APEX END OF SAID CONICAL SECTION, SAID MEANS DEFINING SAID ELUTRIATION CHAMBER HAVING A CYLINDRICAL FORM TO THE END THEREOF CONNECTED TO SAID CONICAL SECTION WHILE ITS REMOTE END HAS A CONICAL FORM THE TIP OF WHICH PROVIDES AN OPENING FROM SAID ELUTRIATION CHAMBER HAVING A DIAMETER EXCEEDING THAT OF SAID CORE, SAID SEPARATING CHAMBER AND HAVING AN INLET FOR TENSION OF SAID SEPARATING CHAMBER AND HAVING AN INLET FOR TANGENTIAL INFLOW OF A SUPPLEMENTAL LIQUID AT A LOCATION ADJACENT SAID APEX END OF SAID CONICAL SECTION TO PRODUCE THEREBY A CONTINUATION OF THE COUNTERFLOWING COLUMNS 